User's Manual

TSS 2. Generation
Tire Safety System TSS 2nd. Generation
Dept. BEE
Dokument Nr.:
Document no.:
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Index:
Index:
3530.001.002.00.27
00 c
Systembeschreibung TSS
System description TSS
freigegeben am /date of release
17/01/07
3 Warning algorithm
The system monitors a nominal pressure, which is set by the operator, and a fixed set minimum warning
pressure. The higher value in each case is used to generate the breakdown warning.
The driver instructs the system to accept the current pressure values as the nominal pressure by using the
“Reset”. The reset is triggered by pressing a key or selecting a menu item.
3.1 Warning limit “Minimum pressure”
At this warning limit, a check is made against the minimum warning pressure P
Warning_MinimumPressure
, which is
programmed into the system as a fixed value.
The minimum warning pressure amounts to 2.6bar abs plus an accuracy reserve of 0.1bar.
The corresponding warning bit is set, if the measured pressure lies below this threshold twice in succession.
3.2 Warning limit “Nominal pressure minus relative deviation”
(Nominal pressure – x %)
This warning limit is calculated from the nominal pressure less a relative deviation of 25% of the nominal
pressure. The nominal pressure is specified by the driver.
Again here an accuracy reserve of 0.1 bar is added to the warning limit.
The corresponding warning bit is set, if the measured pressure lies below this threshold twice in succession.
4 System components
The system components of the TSS system are described below
4.1 Control unit
The control unit consists of a printed circuit board with microcontroller with interfaces for CAN- or K bus and
TSS-Bus.
The software is based on an OSEK Operation System. The tire information received from the digital antenna is
recorded and evaluated in the control unit. The pressure information and, if applicable, the warning information,
is forwarded via the CAN bus to the display systems in the vehicle.
The information from the digital antenna is transferred to the control unit via a so-called TSS Bus
communication. The control unit is the Bus master here, while the antenna or the trigger transmitters work as
slaves. The control unit interrogates the digital antenna at set intervals with respect to radio messages. The
trigger transmitters are contacted in sequence, in order to give them orders with respect to trigger commands
that are to be carried out. The control unit also supplies the supply voltage to the trigger transmitters and the
antenna.
The most important details of the control unit are described below.